package com.huika.dealontop.support.http.rsa;

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.RSAPrivateCrtKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.util.Date;

import javax.crypto.Cipher;

public class RsaHelper {
    /**
     * 生成RSA密钥对(默认密钥长度为1024)
     *
     * @return
     */
    public static KeyPair generateRSAKeyPair() {
        return generateRSAKeyPair(1024);
    }

    /**
     * 生成RSA密钥对
     *
     * @param keyLength 密钥长度，范围：512～2048
     * @return
     */
    public static KeyPair generateRSAKeyPair(int keyLength) {
        try {
            KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA/ECB/PKCS1Padding");
            kpg.initialize(keyLength);
            return kpg.genKeyPair();
        } catch (NoSuchAlgorithmException e) {
            return null;
        }
    }

    /*
     * java端公钥转换成C#公钥
     */
    public static String encodePublicKeyToXml(PublicKey key) {
        if (!RSAPublicKey.class.isInstance(key)) {
            return null;
        }
        RSAPublicKey pubKey = (RSAPublicKey) key;
        StringBuilder sb = new StringBuilder();

        sb.append("<RSAKeyValue>");
        sb.append("<Modulus>").append(Base64Helper.encode(pubKey.getModulus().toByteArray())).append("</Modulus>");
        sb.append("<Exponent>").append(Base64Helper.encode(pubKey.getPublicExponent().toByteArray())).append("</Exponent>");
        sb.append("</RSAKeyValue>");
        return sb.toString();
    }

    /*
     * C#端公钥转换成java公钥
     */
    public static PublicKey decodePublicKeyFromXml(String xml) {
        xml = xml.replaceAll("\r", "").replaceAll("\n", "");
        BigInteger modulus = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<Modulus>", "</Modulus>")));
        BigInteger publicExponent = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<Exponent>", "</Exponent>")));

        RSAPublicKeySpec rsaPubKey = new RSAPublicKeySpec(modulus, publicExponent);

        KeyFactory keyf;
        try {
            keyf = KeyFactory.getInstance("RSA");
            return keyf.generatePublic(rsaPubKey);
        } catch (Exception e) {
            return null;
        }
    }

    /*
     * C#端私钥转换成java私钥
     */
    public static PrivateKey decodePrivateKeyFromXml(String xml) {
        xml = xml.replaceAll("\r", "").replaceAll("\n", "");
        BigInteger modulus = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<Modulus>", "</Modulus>")));
        BigInteger publicExponent = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<Exponent>", "</Exponent>")));
        BigInteger privateExponent = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<D>", "</D>")));
        BigInteger primeP = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<P>", "</P>")));
        BigInteger primeQ = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<Q>", "</Q>")));
        BigInteger primeExponentP = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<DP>", "</DP>")));
        BigInteger primeExponentQ = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<DQ>", "</DQ>")));
        BigInteger crtCoefficient = new BigInteger(1, Base64Helper.decode(getMiddleString(xml, "<InverseQ>", "</InverseQ>")));

        RSAPrivateCrtKeySpec rsaPriKey = new RSAPrivateCrtKeySpec(modulus, publicExponent, privateExponent, primeP, primeQ, primeExponentP, primeExponentQ, crtCoefficient);

        KeyFactory keyf;
        try {
            keyf = KeyFactory.getInstance("RSA");
            return keyf.generatePrivate(rsaPriKey);
        } catch (Exception e) {
            return null;
        }
    }

    /*
     * java端私钥转换成C#私钥
     */
    public static String encodePrivateKeyToXml(PrivateKey key) {
        if (!RSAPrivateCrtKey.class.isInstance(key)) {
            return null;
        }
        RSAPrivateCrtKey priKey = (RSAPrivateCrtKey) key;
        StringBuilder sb = new StringBuilder();

        sb.append("<RSAKeyValue>");
        sb.append("<Modulus>").append(Base64Helper.encode(priKey.getModulus().toByteArray())).append("</Modulus>");
        sb.append("<Exponent>").append(Base64Helper.encode(priKey.getPublicExponent().toByteArray())).append("</Exponent>");
        sb.append("<P>").append(Base64Helper.encode(priKey.getPrimeP().toByteArray())).append("</P>");
        sb.append("<Q>").append(Base64Helper.encode(priKey.getPrimeQ().toByteArray())).append("</Q>");
        sb.append("<DP>").append(Base64Helper.encode(priKey.getPrimeExponentP().toByteArray())).append("</DP>");
        sb.append("<DQ>").append(Base64Helper.encode(priKey.getPrimeExponentQ().toByteArray())).append("</DQ>");
        sb.append("<InverseQ>").append(Base64Helper.encode(priKey.getCrtCoefficient().toByteArray())).append("</InverseQ>");
        sb.append("<D>").append(Base64Helper.encode(priKey.getPrivateExponent().toByteArray())).append("</D>");
        sb.append("</RSAKeyValue>");
        return sb.toString();
    }

    // 用公钥加密
    public static byte[] encryptData(byte[] data, PublicKey pubKey) {
        try {
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            cipher.init(Cipher.ENCRYPT_MODE, pubKey);
            return cipher.doFinal(data);
        } catch (Exception e) {
            return null;
        }
    }

    // 用私钥解密
    public static byte[] decryptData(byte[] encryptedData, PrivateKey priKey) {
        try {
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, priKey);
            return cipher.doFinal(encryptedData);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * 根据指定公钥进行明文加密
     *
     * @param plainText 要加密的明文数据
     * @param pubKey    公钥
     * @return
     */
    public static String encryptDataFromStr(String plainText, PublicKey pubKey) {
        try {
            byte[] dataByteArray = plainText.getBytes("gb2312");
            byte[] encryptedDataByteArray = RsaHelper.encryptData(dataByteArray, pubKey);
            return Base64Helper.encode(encryptedDataByteArray);
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return "";
        }
    }

    /**
     * 根据指定私钥对数据进行签名(默认签名算法为"SHA1withRSA")
     *
     * @param data   要签名的数据
     * @param priKey 私钥
     * @return
     */
    public static byte[] signData(byte[] data, PrivateKey priKey) {
        return signData(data, priKey, "SHA1withRSA");
    }

    /**
     * 根据指定私钥和算法对数据进行签名
     *
     * @param data      要签名的数据
     * @param priKey    私钥
     * @param algorithm 签名算法
     * @return
     */
    public static byte[] signData(byte[] data, PrivateKey priKey, String algorithm) {
        try {
            Signature signature = Signature.getInstance(algorithm);
            signature.initSign(priKey);
            signature.update(data);
            return signature.sign();
        } catch (Exception ex) {
            return null;
        }
    }

    /**
     * 用指定的公钥进行签名验证(默认签名算法为"SHA1withRSA")
     *
     * @param data   数据
     * @param sign   签名结果
     * @param pubKey 公钥
     * @return
     */
    public static boolean verifySign(byte[] data, byte[] sign, PublicKey pubKey) {
        return verifySign(data, sign, pubKey, "SHA1withRSA");
    }

    /**
     * @param data      数据
     * @param sign      签名结果
     * @param pubKey    公钥
     * @param algorithm 签名算法
     * @return
     */
    public static boolean verifySign(byte[] data, byte[] sign, PublicKey pubKey, String algorithm) {
        try {
            Signature signature = Signature.getInstance(algorithm);
            signature.initVerify(pubKey);
            signature.update(data);
            return signature.verify(sign);
        } catch (Exception ex) {
            return false;
        }
    }

    public static void main(String[] args) {
        KeyPair kp = RsaHelper.generateRSAKeyPair();
        PublicKey pubKey = kp.getPublic();
        PrivateKey priKey = kp.getPrivate();

        String pubKeyXml = RsaHelper.encodePublicKeyToXml(pubKey);
        String priKeyXml = RsaHelper.encodePrivateKeyToXml(priKey);
        System.out.println("====公钥====");
        System.out.println(pubKeyXml);
        System.out.println("====私钥====");
        System.out.println(priKeyXml);

        PublicKey pubKey2 = RsaHelper.decodePublicKeyFromXml(pubKeyXml);
        PrivateKey priKey2 = RsaHelper.decodePrivateKeyFromXml(priKeyXml);

        System.out.println("====公钥对比====");
        System.out.println(pubKey.toString());
        System.out.println("------");
        System.out.println(pubKey2.toString());

        System.out.println("====私钥对比====");
        System.out.println(priKey.toString());
        System.out.println("------");
        System.out.println(priKey2.toString());

        try {
            String pubKeyXml3 = "<RSAKeyValue><Modulus>rHESyuI3ny4MLsqDBalW9ySaodCL0e6Bsrl01Q5G1qm2wjUoGULazZSNqZY+JQNjU92tW3Snk5RPIkv+wDj+uOT9LTUjQImltHnzqMvbt06GipVXDOyBLTa7G/zRIe/CrjyJ+XEYX2xIhpe5ayowl3HHUpZ71jRNioyxaVVZ8S0=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";
            String priKeyXml3 = "<RSAKeyValue><Modulus>rHESyuI3ny4MLsqDBalW9ySaodCL0e6Bsrl01Q5G1qm2wjUoGULazZSNqZY+JQNjU92tW3Snk5RPIkv+wDj+uOT9LTUjQImltHnzqMvbt06GipVXDOyBLTa7G/zRIe/CrjyJ+XEYX2xIhpe5ayowl3HHUpZ71jRNioyxaVVZ8S0=</Modulus><Exponent>AQAB</Exponent><P>5a7uM+IeY8QMVQl0q88ZTqWbB555l7+366cUIClTN8z2ZXzTnWFCNoQzUrG14FouJFYumFZD12Ni5MkJK6gqSw==</P><Q>wDMhwwO4kz82uSG+FlCBr06fYk2COTg0TofmSp/5OrVqgkBIe7FgpTpVGzGLk0mvOLcy6UZftq//W0Saow6nZw==</Q><DP>FbjDgliiMyE5YVlxlUYSyKNU1BWivj09caXte1UtL5vMubBiewHVtz4tdGamIr+kmX8lDPcrl1Uo5yY0HdLbnQ==</DP><DQ>kIjjJsgxkWnEOUyKqjU4kSDK8x3ehDEkBLpmEFBlGCU9R14YJAyr5RUM0zpbABQ1VK1P9+UYLUYE/hmFQIHQmQ==</DQ><InverseQ>pxQDThwSnUZ4EaNaCPl1ovYypdQUZaZ/Sld1+0n8FEjkmRcGP1R9VMuj1ViPZg3rvm2GeP8Xv1SJqJUVueWiGA==</InverseQ><D>DxBNoPWEAF7IZ6n/KhZx52MGMw6BuFQKdm9m+lml7Iik03BLUXGapYzNlzvtr9QM8D2UMEIPhX/WLdvPpEEWVzGnD7XpLXjGwfu1ZkJRcXPEZEZ2subh5ZBqOWCFWKv5WwgGYWuYDLHfrBlBgSFWR8cZuyqkmMsWl4CiadXqGA0=</D></RSAKeyValue>";

            System.out.println((new Date()).toLocaleString() + ": 加载公钥中。。。");
            PublicKey pubKey3 = RsaHelper.decodePublicKeyFromXml(pubKeyXml3);
            System.out.println((new Date()).toLocaleString() + ": 加载私钥中。。。");
            PrivateKey priKey3 = RsaHelper.decodePrivateKeyFromXml(priKeyXml3);

            String dataStr = "Java与.NET和平共处万岁！";
            byte[] dataByteArray = dataStr.getBytes("utf-8");
            System.out.println("data的Base64表示：" + Base64Helper.encode(dataByteArray));

            System.out.println((new Date()).toLocaleString() + ": 加密中。。。"); // 加密
            byte[] encryptedDataByteArray = RsaHelper.encryptData(dataByteArray, pubKey3);

            System.out.println("encryptedData的Base64表示：" + Base64Helper.encode(encryptedDataByteArray));
            System.out.println((new Date()).toLocaleString() + ": 解密中。。。"); // 解密
            // byte[]
            byte[] decryptedDataByteArray = RsaHelper.decryptData(encryptedDataByteArray, priKey3);
            System.out.println(new String(decryptedDataByteArray, "utf-8"));// 签名
            System.out.println((new Date()).toLocaleString() + ": 签名中。。。");
            byte[] signDataByteArray = RsaHelper.signData(dataByteArray, priKey3);
            System.out.println("signData的Base64表示：" + Base64Helper.encode(signDataByteArray)); // 验签
            System.out.println((new Date()).toLocaleString() + ": 验签中。。。");
            boolean isMatch = RsaHelper.verifySign(dataByteArray, signDataByteArray, pubKey3);
            System.out.println("验签结果：" + isMatch);

        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    /**
     * 返回两个字符串中间的内容
     *
     * @param all
     * @param start
     * @param end
     * @return
     */
    public static String getMiddleString(String all, String start, String end) {
        int beginIdx = all.indexOf(start) + start.length();
        int endIdx = all.indexOf(end);
        return all.substring(beginIdx, endIdx);
    }
}
